Ben Platt is waving goodbye to “Dear Evan Hansen” (presumably through a window).

His temporary replacement beginning Nov. 21 is Noah Galvin, who previously starred on the ABC sitcom “The Real O’Neals.” Galvin is expected to play Evan through January of 2018 when Taylor Trensch will take over, following his run in “Hello, Dolly!”

“Evan is such a complex and rewarding role, and I can’t wait to see Noah and Taylor make it their own,” director Michael Greif said. “Nothing excites me more than working with young talent, and both young men are incredibly skilled and surprising performers.”

While Platt is stepping aside, Laura Dreyfuss, Rachel Bay Jones, Jennifer Laura Thompson, Mike Faist, Michael Park, and Will Roland have all extended their contracts to remain in the musical through May 2018. Kristolyn Lloyd will stay through February 2018.

“We’re excited to welcome Noah and Taylor to our Dear Evan Hansen Family and I’m deeply joyful that our other original company members will remain in our show,” producer Stacey Mindich said. “As we embark on casting for the national tour and future productions of the show, it’s thrilling to begin discovering new, exciting talent for this unique role.”

“Dear Evan Hansen” won six Tonys at the 2017 awards, including the prize for best musical. The music and lyrics are by Benj Pasek and Justin Paul, and the book comes from Steven Levenson.

Trensch can be seen as Barnaby Tucker in the revival of “Hello Dolly!” starring Bette Midler. Galvin played the central character, Kenny O’Neal, in “The Real O’Neals” which was canceled in May after two seasons.